What is toric lens?

[Chance]

I often see ads in sunglasses,"toric lens",what does it mean?

[Drake]

A toric lens is a lens with two different powers in two orientations perpendicular to each other. One of the lens surfaces is shaped like a "cap" from a torus (see figure at right), while the other one usually is spherical. Toric lenses are primarily used in eyeglasses, contact lenses and intraocular lenses, to correct for astigmatism.

[Zane]

Toric lenses are a type of contact lens which are used to correct astigmatism. Unlike regular contact lenses, toric lenses are designed for two purposes, one is for correcting astigmatism and one is for correcting vision.